David Kroll
, ContributorOpinions expressed by Forbes Contributors are their own.

Cauliflower (Photo credit: Wikipedia)

Across the Forbes.com platform yesterday Jon Entine, Executive Director of the Genetic Literacy Project, offered an op-ed on concerns regarding the existence of plant virus DNA sequences in transgenic plant food products. Read his article and the comment thread to see the concerns.

My apologies in advance to those not well versed in the technical jargon of plant molecular biology but here's my response to those deeply-engaged in promulgating the concerns about this viral DNA sequence:

2. The viral DNA would have to be successfully taken up by our cells in the gut, or microbes that live in our gut.

3. The transfer would have to occur in a very high percentage of cells.

4. The 35S promoter would have to be somehow spliced out of the plant DNA and be successfully transferred into an area of human DNA where it might drive a harmful gene.

5. The 35S promoter, while highly-effective in plants, would have to somehow have gene promoter activity in human cells (or gut microbes).

A few scientific reports do show that some of these effects might occur in highly-specialized environments that are designed to make "something" happen.

For example, one 2006 paper (PDF) shows that foreign gene expression driven by the 35S promoter can occur in a special "enterocyte-like" cell line (Caco-2, for those in the biz) if you 1) hammer high amounts of a specially-designed DNA construct 2) coated with a special combination of lipids designed to get the DNA into the cells that is 3) engineered to make the activity of a high-sensitivity enzyme (firefly luciferase) or high-sensitive protein (jellyfish green fluorescent protein) appear.

So, one can make "something" happen if one has a preconceived conclusion and the experiments are designed to produce this change using heroic, non-natural techniques. And that's just one of the five rare-to-impossible factors that would have to occur in combination for there to be any risk of ingesting transgenic plant products containing the 35S gene promoter.

Remember, the viral identity of the 35S promoter in no way affects how the DNA might be transferrable. The 35S promoter does not drive the expression of any genes involved in viral infection of the plants. It merely drives high-level expression of target genes in the transgenic plant.

I'm in no way saying that we shouldn't test GMO, transgenic food plants for long-term safety issues. My first college degree was in toxicology, the science of substances with the potential for adverse effects. So let's do the experiments.

But let's do them under real-world conditions, not in some artificial and heroic system designed to see some small event of questionable human significance.

One last note: We ingest foreign DNA every day: gene promoter DNA sequences from traditionally-bred corn, beans, yeast, lettuce, bacteria, onions, cucumbers, tomatoes, potatoes, collard greens, cabbage, (and chicken, beef, pork, lamb, etc. for non-vegetarians) as well as all manner of viruses that can normally affect each of these organisms.

Pass me another plate.

This post originally carried the title, "A Combination of Unusual, Rare-to-Impossible Events Would Be Required for the CaMV 35S DNA Sequence to be a GMO Human HealthRisk."